function calling in c++

Question

Where Im mistaking. It says that number variable is not initialized.

#include <iostream>
using namespace std;
int ispisi_broj(int a) {

    cout << " Input number: ";
    cin >> a;
    cout << a;
    return 0;
}
int main() {
    int number; 
    ispisi_broj(number);

You must pass `number` by reference, so declare `a` as `int& a`. — Etienne de Martel, Aug 10 '22 at 18:19
`ispisi_broj(number);` makes a copy of the variable `number`. Which is not initialized. — Drew Dormann, Aug 10 '22 at 18:20
Recommendation: Rather than passing in parameter `a`, read into a local variable and return it. Eg `int ispisi_broj() { int a; /* blah blah blah */ return a; }` and then `int number; = ispisi_broj();`. — user4581301, Aug 10 '22 at 18:22
Correction to above: `int number; = ispisi_broj();` should be `int number = ispisi_broj();` — user4581301, Aug 10 '22 at 18:28
Create function ispisi_broj(int a) which takes number a of int type as a parameter , and writes it. Then call it from main program. Use cin operator — Slavoljub Radosavljevic, Aug 10 '22 at 18:29
*takes number a of int type as a parameter , and writes it.* reads to me as `ispisi_broj` should merely print `a`, not read the value in from the user. Reading in the value should be done elsewhere, probably in `main`. — user4581301, Aug 10 '22 at 18:36

score 0 · Answer 1 · answered Aug 10 '22 at 18:30

In this function

int ispisi_broj(int a) {

    cout << " Input number: ";
    cin >> a;
    cout << a;
    return 0;
}

the value of the parameter a is not used because it is at once reassigned in this statement

cin >> a;

So the function declaration does not make a great sense.

Also the return type int of the function also does not make a sense.

It seems you mean the following

#include <iostream>
using namespace std;

void ispisi_broj( int &a ) 
{
    cout << " Input number: ";
    cin >> a;
}

int main() 
{
    int number; 

    ispisi_broj(number);

    cout << " Input number: ";
    cout << a << '\n';
    return 0;
}

That is if you want to change the variable number declared in main within the function ispisi_broj then you need to pass it to the function by reference.

function calling in c++

1 Answers1